prog.c:26:6: warning: implicit declaration of function 'getch' is invalid in C99 [-Wimplicit-function-declaration]
getch();
^
prog.c:4:16: warning: unused variable 'j' [-Wunused-variable]
int n, i, j, bin_rev=0,bin=0;
^
2 warnings generated.
/home/fGWGh4/prog-b38c8a.o: In function `main':
prog.c:(.text+0xc1): undefined reference to `getch'
clang: error: linker command failed with exit code 1 (use -v to see invocation)